SPID#: 48 One of the most important issues in animal management is to determine the optimal captive environment for the physical and psychological well-being of a particular species. Estimates of well-being require data on behavior, physiology, trauma, health, and reproduction of animals kept under different conditions. The present project seeks to provide this information for species used as AIDS animal models, such as the chimpanzee (Pan troglodytes), rhesus macaque (Macaca mulatta), and pigtail macaque (M. nemestrina). Data collected on these three species under a variety of conditions with standardized protocols will provide a computerized data base (supplemented with a behavior manual and video material) that will enhance the ability of national breeding programs to justify existing housing conditions and/or provide an empirical basis for the design of future facilities. The project is also part of an ongoing effort to develop a new theoretical model of environmental effects on aggressive behavior. Nonhuman primates have many checks on aggression, and appear to effectively cope with social tension related to crowding through appeasement and conflict resolution. In 1995 data were collected on 50 chimpanzees living in three different groups. Two groups live in outdoor compounds, the third is housed in indoor/outdoor runs Data collection consisted of behavioral observation, injury checks, and fecal sampling. The latter was done to assess stress hormones such as cortisol. Preliminary analysis shows that chimpanzees reduce their social activity level as a short-term response to increased density. Chimpanzees were also found to respond to the vocalizations of neighboring groups by increasing various forms of agonism. Behavioral observations have also been made on a group of 49 pigtail macaques. Video images of the three species were taken and catalogued according to their behavioral contents.